Explanipedia

ScarFinder: A Detector of Optimal Scar Trajectories in Quantum Many-Body Dynamics Open

Jie Ren, Andrew Hallam, Lei Ying, Zlatko Papić · 2025

Mechanisms that give rise to coherent quantum dynamics, such as quantum many-body scars, have recently attracted much interest as a way of controlling quantum chaos. However, identifying the presence of quantum scars in general many-body H…

Window-Based Feature Engineering for Cognitive Workload Detection Open

Andrew Hallam, R G Gayathri, Tsz-Kwan Lee, Atul Sajjanhar · 2025

Cognitive workload is a topic of increasing interest across various fields such as health, psychology, and defense applications. In this research, we focus on classifying cognitive workload using the COLET dataset, employing a window-based…

Tunable quantum Mpemba effect in long-range interacting systems Open

Andrew Hallam, M. Yusuf, Aashish A. Clerk, Ivar Martin, Zlatko Papić · 2025

Symmetry plays a fundamental role in many-body systems, both in and out of equilibrium. The quantum Mpemba effect (QME) - a phenomenon where systems initially farther from equilibrium can thermalize faster - can be understood in terms of h…

Entanglement and apparent thermality in simulated black holes Open

Iason A. Sofos, Andrew Hallam, Jiannis K. Pachos · 2025

We investigate the apparent thermality of Hawking radiation in the semi-classical limit of quantum black holes using the mean-field limit of a chiral spin-chain simulator, which models fermions propagating on a black hole space-time in the…

Social Workers as Politicians: The Key Factors Influencing  Social Workers to Participate as Candidates in Political Elections in Australia Open

Andrew Hallam, Philip Mendes · 2025

This study examines the key factors that influence social workers to run for political office in Australia. Eleven in-depth, semi-structured interviews were conducted with social workers who had either run for election, or been elected to,…

Optimally scrambling chiral spin-chain with effective black hole geometry Open

Aiden Daniel, Andrew Hallam, Matthew D. Horner, Jiannis K. Pachos · 2025

Stirring the false vacuum via interacting quantized bubbles on a 5,564-qubit quantum annealer Open

Jaka Vodeb, Jean-Yves Desaules, Andrew Hallam, Andrea Rava, Gregor Humar , et al. · 2025

False vacuum decay—the transition from a metastable quantum state to a true vacuum state—plays an important role in quantum field theory and non-equilibrium phenomena such as phase transitions and dynamical metastability. The non-perturbat…

Non-stabilizerness in kinetically-constrained Rydberg atom arrays Open

Ryan P. Smith, Zlatko Papić, Andrew Hallam · 2024

Non-stabilizer states are a fundamental resource for universal quantum computation. However,despite broad significance in quantum computing, the emergence of "many-body" non-stabilizerness in interacting quantum systems remains poorly unde…

Stirring the false vacuum via interacting quantized bubbles on a 5564-qubit quantum annealer Open

Jaka Vodeb, Jean-Yves Desaules, Andrew Hallam, Andrea Rava, Gregor Humar , et al. · 2024

False vacuum decay is a potential mechanism governing the evolution of the early Universe, with profound connections to non-equilibrium quantum physics, including quenched dynamics, the Kibble-Zurek mechanism, and dynamical metastability. …

Optimally scrambling chiral spin-chain with effective black hole geometry Open

Aiden Daniel, Andrew Hallam, Matthew D. Horner, Jiannis K. Pachos · 2024

There is currently significant interest in emulating the essential characteristics of black holes, such as their Hawking radiation or their optimal scrambling behavior, using condensed matter models. In this article, we investigate a chira…

Integrability Breaking and Bound States in Google’s Decorated XXZ Circuits Open

Ana Hudomal, Ryan Smith, Andrew Hallam, Zlatko Papić · 2024

Recent quantum simulation by Google [Nature , 240 (2022)] has demonstrated the formation of bound states of interacting photons in a quantum-circuit version of the XXZ spin chain. While such bound states are protected by integrability in a…

Exploring interacting chiral spin chains in terms of black hole physics Open

E. G. Forbes, Matthew D. Horner, Andrew Hallam, Joseph Barker, Jiannis K. Pachos · 2023

In this paper we explore the properties of a one-dimensional spin chain in the presence of chiral interactions, focusing on the system's transition to distinct chiral phases for various values of the chiral coupling. By employing the mean-…

Embedding Semiclassical Periodic Orbits into Chaotic Many-Body Hamiltonians Open

Andrew Hallam, Jean-Yves Desaules, Zlatko Papić · 2023

Protecting coherent quantum dynamics from chaotic environment is key to realizations of fragile many-body phenomena and their applications in quantum technology. We present a general construction that embeds a desired periodic orbit into a…

Integrability breaking and bound states in Google's decorated XXZ circuits Open

Ana Hudomal, Ryan Smith, Andrew Hallam, Zlatko Papić · 2023

Recent quantum simulation by Google [Nature 612, 240 (2022)] has demonstrated the formation of bound states of interacting photons in a quantum-circuit version of the XXZ spin chain. While such bound states are protected by integrability i…

Bridging quantum criticality via many-body scarring Open

Aiden Daniel, Andrew Hallam, Jean-Yves Desaules, Ana Hudomal, Guo-Xian Su , et al. · 2023

Quantum dynamics in certain kinetically-constrained systems can display a strong sensitivity to the initial condition, wherein some initial states give rise to persistent quantum revivals---a type of weak ergodicity breaking known as ``qua…

Exploring interacting chiral spin chains in terms of black hole physics Open

E. G. Forbes, Matthew D. Horner, Andrew Hallam, Joseph Barker, Jiannis K. Pachos · 2023

In this paper we explore the properties of a 1-dimensional spin chain in the presence of chiral interactions, focusing on the system's transition to distinct chiral phases for various values of the chiral coupling. By employing the mean fi…

Embedding semiclassical periodic orbits into chaotic many-body Hamiltonians Open

Andrew Hallam, Jean-Yves Desaules, Zlatko Papić · 2023

Protecting coherent quantum dynamics from chaotic environment is key to realizations of fragile many-body phenomena and their applications in quantum technology. We present a general construction that embeds a desired periodic orbit into a…

Bridging quantum criticality via many-body scarring Open

Aiden Daniel, Andrew Hallam, Jean-Yves Desaules, Ana Hudomal, Guoxian , et al. · 2023

Quantum dynamics in certain kinetically-constrained systems can display a strong sensitivity to the initial condition, wherein some initial states give rise to persistent quantum revivals -- a type of weak ergodicity breaking known as `qua…

Chiral Spin-Chain Interfaces Exhibiting Event-Horizon Physics Open

Matthew D. Horner, Andrew Hallam, Jiannis K. Pachos · 2023

The interface between different quantum phases of matter can give rise to novel physics, such as exotic topological phases or nonunitary conformal field theories. Here we investigate the interface between two spin chains in different chira…

Tuning between Continuous Time Crystals and Many-Body Scars in Long-Range Spin Chains Open

Kieran Bull, Andrew Hallam, Zlatko Papić, Ivar Martin · 2022

Persistent oscillatory dynamics in nonequilibrium many-body systems is a tantalizing manifestation of ergodicity breakdown that continues to attract much attention. Recent works have focused on two classes of such systems: discrete time cr…

Tuning between continuous time crystals and many-body scars in long-range XYZ spin chains Open

Kieran Bull, Andrew Hallam, Zlatko Papić, Ivar Martin · 2022

Persistent oscillatory dynamics in non-equilibrium many-body systems is a tantalizing manifestation of ergodicity breakdown that continues to attract much attention. Recent works have focused on two classes of such systems: discrete time c…

Emergence of gaussianity in the thermodynamic limit of interacting fermions Open

Gabriel Matos, Andrew Hallam, Aydin Deger, Zlatko Papić, Jiannis K. Pachos · 2021

Systems of interacting fermions can give rise to ground states whose correlations become effectively free-fermion-like in the thermodynamic limit, as shown by Baxter for a class of integrable models that include the one-dimensional XYZ spi…

Phase Transitions in the Classical Simulability of Open Quantum Systems Open

F. Azad, Andrew Hallam, James G. Morley, A. G. Green · 2021

We study the evolution of an open quantum system using a Langevin unravelling of the density matrix evolution over matrix product states. As the strength of coupling to and temperature of the environment is increased, we find a transition …

Emergence of Gaussianity in the thermodynamic limit of interacting\n fermions Open

Gabriel Matos, Andrew Hallam, Aydin Deger, Zlatko Papić, Jiannis K. Pachos · 2021

Systems of interacting fermions can give rise to ground states whose\ncorrelations become effectively free-fermion-like in the thermodynamic limit,\nas shown by Baxter for a class of integrable models that include the\none-dimensional XYZ …

Entanglement compression in scale space: From the multiscale entanglement renormalization ansatz to matrix product operators Open

Karel Van Acoleyen, Andrew Hallam, Matthias Bal, Markus Hauru, Jutho Haegeman , et al. · 2020

The multiscale entanglement renormalization ansatz (MERA) provides a\nconstructive algorithm for realizing wavefunctions that are inherently scale\ninvariant. Unlike conformally invariant partition functions however, the finite\nbond dimen…

The Lyapunov spectra of quantum thermalisation Open

Andrew Hallam, Jeremy Morley, A. G. Green · 2019

Compact Neural Networks based on the Multiscale Entanglement Renormalization Ansatz Open

Andrew Hallam, Edward Grant, Vid Stojevic, Simone Severini, A. G. Green · 2017

This paper demonstrates a method for tensorizing neural networks based upon an efficient way of approximating scale invariant quantum states, the Multi-scale Entanglement Renormalization Ansatz (MERA). We employ MERA as a replacement for t…

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